1. Field of the Invention
The present invention relates to a method of manufacturing a multi-layer circuit board, and to the multi-layer circuit board.
2. Description of the Related Art
Regarding multi-layer circuit boards in which an inner layer substrate including an inner layer circuit and an outer layer substrate including an outer layer circuit are stacked, a method of manufacturing such a multi-layer circuit board that has a structure exposing a part of the inner layer circuit disclosed in Unexamined Japanese Patent Application Publication No. 2010-206124 A is known (refer to, Document 1). This multi-layer circuit board is manufactured as follows. That is, the outer layer substrate is stacked on a surface of a terminal exposure side of the inner layer circuit of the inner layer substrate, via an interlayer adhesive layer including an opening which is larger than an exposed portion of the terminal.
Moreover, a pair of slits is formed in the outer layer substrate at positions outside the opening of the interlayer adhesive layer so as to sandwich a portion eventually to be removed, and the outer layer circuit of the outer layer substrate is formed. Finally, a punching processing is implemented straddling the slits to expose a terminal portion of the inner surface circuit. In this way for manufacturing the multi-layer circuit board, a structure that the interlayer adhesive layer is attached a terminal side end of the slits is formed after stacking, then the slits are closed by the inter-layer adhesive layer. Thus making it possible to prevent intrusion of chemicals into the terminal portion while forming the outer layer circuit by etching, and so on.